Free rotary fluid machine

ABSTRACT

There is provided a free rotary fluid machine including: a main body which is provided in a hollow cylindrical shape, and has an elliptical inner circumferential surface; a rotor which is provided in the main body, and rotates about the same rotation center as the main body; tip seals which are provided at one side of the rotor so as to be in contact with the inner circumferential surface of the main body; and blades which are provided between the tip seals provided adjacent to each other, and supported by the tip seals, in which the blade has one end surface that faces the inner circumferential surface of the main body, and the other end surface that is opposite to one end surface, and centers of radii of curvature of one end surface and the other end surface are positioned at the same side. As described above, a space formed among the inner circumferential surface of the main body, the rotor, and the tip seal is sealed by the auxiliary tip seal, and as a result, it is possible to reduce friction between the tip seal and the main body and to prevent a leak of an introduced working fluid.

TECHNICAL FIELD

The present invention relates to a fluid machine, and more particularly, to a free rotary fluid machine in which an auxiliary tip seal is formed in a tip seal, such that a space formed by a main body, a rotor, and a tip seal is sealed by improving performance of the main body and the tip seal when the rotor is rotated, thereby preventing a leak of an introduced working fluid.

BACKGROUND ART

In general, an internal combustion engine, which is widely used for various types of vehicles, ships, aircrafts, tractors, locomotives, and the like, has a piston that rectilinearly moves in a cylinder of the engine, such that the piston is moved downward by explosive power of fuel, and a crank rod, which is connected to the piston, is connected to the crank shaft so as to convert the rectilinear downward movement of the piston in terms of a rotational motion of the crank shaft, thereby obtaining rotational power.

A typical internal combustion engine in the related art has a problem in that impact and friction caused by the piston are not unevenly applied to the crank shaft when the crank shaft and the crank rod mechanically convert a rectilinear motion into a rotational motion, such that noise and vibration severely occur, mechanical durability deteriorates, efficiency greatly deteriorates, and particularly, a material such as a ceramic material vulnerable to impact cannot be used.

Meanwhile, to solve the problems of the existing internal combustion engine, there has been developed a rotary engine having a simple structure in which a plurality of explosion spaces is provided in a rotor, and an air inlet port and a gas discharge port are formed outside the rotor, such that fuel or a fluid is supplied to the explosion spaces, the explosion spaces are rotated by rotational force of the rotor, combustion gas may be naturally discharged when the explosion space meets the gas discharge port, and air may be naturally introduced when the explosion space meets the air inlet port.

However, the rotary engine cannot solve the defects of the existing internal combustion engine, and has serious problems in that combustion gas in the rotary engine cannot be completely discharged, and air cannot be completely introduced, and as a result, driving performance and efficiency extremely deteriorate, air and combustion gas are insufficiently introduced and discharged when the rotary engine operates at a low speed, and air and combustion gas are excessively introduced and discharged when the rotary engine operates at a high speed.

In addition, vibration and abrasion occur because the rotor of the rotary engine rotates about an eccentric axis, and a Wankel engine, which is known as a representative rotary engine, has a problem in that vibration inevitably occurs and durability and airtightness deteriorate because a rotor rotates eccentrically about a rotating shaft.

To solve the aforementioned problems, the applicant of the present application has proposed Korean Patent No. 10-0652557 (registration date: Nov. 24, 2006) entitled “free piston rotary engine”. However, the technology disclosed in Korean Patent No. 10-0652557 has problems in that because a contact area between a blade and a tip seal is small, a contact state between the blade and the tip seal is not maintained when centrifugal force, which occurs when a rotor rotates, is applied to the blade, and the blade deviates outward in a direction in which the centrifugal force is applied, and as a result, the blade cannot rotate, such that the rotary engine cannot be used. Further, the technology has problems in that vibration and abrasion still occur on the rotor due to a sliding motion between the rotor and the tip seal, and as a result, durability and airtightness of the rotary engine deteriorate.

Furthermore, when centrifugal force caused by the rotation is applied to the blade, the blade is withdrawn from the tip seal, and the blade collides with a stator, and as a result, the rotor cannot be rotated. Further, there is a problem in that a contact state of the tip seal is deformed, such that a leak occurs in a combustion chamber, a collision occurs as the blade moves, or abrasion occurs.

Meanwhile, the technology disclosed in Korean Patent No. 10-0652557 is described as being applied to an engine which uses gasoline, diesel, hydrogen, and the like as fuel, and Korean Patent No. 10-0652557 also describes that the technology may also be used for a turbine that uses any one of steam, air, and gas.

However, the structure of the engine disclosed in Korean Patent No. 10-0652557 may be substantially applied only to the engine, but there is a limitation in applying the structure to a turbine and a compressor.

DISCLOSURE Technical Problem

An aspect of the present invention provides a free rotary fluid machine in which close contact performance between a tip seal and an inner circumferential surface of a main body is improved even though the tip seal, which is in contact with the inner circumferential surface of the main body, is abraded when a rotor is rotated in the main body, such that a volume space formed among the inner circumferential surface of the main body, a blade, and the tip seal is sealed, thereby preventing a leak of an introduced working fluid.

An aspect of the present invention also provides a free rotary fluid machine capable of maintaining a surface-to-surface contact state between a blade and a tip seal even though centrifugal force is applied to the blade.

Technical Solution

According to an aspect of the present invention, there is provided a free rotary fluid machine including: a main body which is provided in a hollow cylindrical shape, and has an elliptical inner circumferential surface; a rotor which is provided in the main body, and rotates about the same rotation center as the main body; tip seals which are provided at one side of the rotor so as to be in contact with the inner circumferential surface of the main body; and blades which are provided between the tip seals provided adjacent to each other, and supported by the tip seals, in which the blade has one end surface that faces the inner circumferential surface of the main body, and the other end surface that is opposite to one end surface, and centers of radii of curvature of one end surface and the other end surface are positioned at the same side.

The blade may have tip seal contact portions that connect one end surface and the other end surface, and the tip seal contact portion may be formed to have the same curved surface as the tip seal.

One end portion of the tip seal in a longitudinal direction of the tip seal may be formed in a cylindrical shape having a circular cross section and may be in contact with the inner circumferential surface of the main body, the other end portion of the tip seal may be formed in a hexahedral bar shape having a quadrangular cross section, and the tip seal contact portion may be in surface-to-surface contact with one end portion from a point at which one end portion meets the other end portion.

A portion where the tip seal contact portion meets one end portion may be formed to have a curved surface.

An auxiliary tip seal, which is formed to protrude toward the inner circumferential surface of the main body, may be provided at one end portion of the tip seal, and the auxiliary tip seal may be rotated by the rotor while maintaining a surface-to-surface contact state with the inner circumferential surface of the main body.

The auxiliary tip seal may include: a sealing member which is drawn in or pulled out from the tip seal; and an elastic support body which supports the sealing member and enables the sealing member to be drawn in or pulled out from the tip seal.

The sealing member may be made of a ceramic material.

The free rotary fluid machine may further include a pressing member which is provided between the tip seal and the rotor and elastically presses the tip seal.

A width of the sealing member may be smaller than a width of an opening which is formed at one end portion of the tip seal such that the sealing member is inserted into the opening.

At least one intake port and at least one exhaust port may be provided in the main body, and the intake port and the exhaust port may be provided radially based on the rotation center of the main body.

Advantageous Effects

According to the exemplary embodiments of the present invention, a space formed among the inner circumferential surface of the main body, the rotor, and the tip seal is sealed by the auxiliary tip seal, and as a result, it is possible to reduce friction between the tip seal and the main body and to prevent a leak of the introduced working fluid.

In addition, according to the exemplary embodiments of the present invention, since the auxiliary tip seal is drawn in and pulled out from the tip seal, a position of the blade, which is supported between the tip seals provided adjacent to each other, may be automatically moved.

In addition, according to the exemplary embodiments of the present invention, the tip seal comes into close contact with the inner circumferential surface of the main body as the tip seal is moved by a length or a thickness of the blade toward the inner circumferential surface of the main body even though no centrifugal force is applied, and the tip seal is forcibly pressed against the inner circumferential surface of the main body even though the tip seal is abraded to any limit point, and as a result, it is possible to maintain performance of the tip seal.

In addition, according to the exemplary embodiments of the present invention, the pressing member is provided between the tip seal and the rotor, and as a result, the tip seal may be retracted toward the rotation center of the rotor or may be moved forward in a direction opposite to the rotation center.

In addition, according to the exemplary embodiments of the present invention, the inner surface and the outer surface of the blade have almost the same shape, and as a result, it is possible to increase an area in which both ends of the blade in the rotation direction of the blade are in contact with the curved surfaces of the tip seals, respectively, and for this reason, the blade and the tip seal may be moved while maintaining the surface-to-surface contact state between both ends of the blade and the tip seals even in a case in which centrifugal force is applied to the blade.

DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view illustrating a rotary fluid machine according to an exemplary embodiment of the present invention;

FIG. 2 is a perspective view illustrating a tip seal illustrated in FIG. 1;

FIG. 3 is a perspective view illustrating a blade illustrated in FIG. 1;

FIG. 4 is a view for explaining a case in which the rotary fluid machine according to the exemplary embodiment of the present invention is a turbine;

FIG. 5 is a view for explaining a case in which the rotary fluid machine according to the exemplary embodiment of the present invention is a compressor; and

FIG. 6 is a view for explaining a case in which the rotary fluid machine according to the exemplary embodiment of the present invention is a compander.

BEST MODE

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the technical field to which the present invention pertains may easily carry out the exemplary embodiment. The present invention may be implemented in various different ways, and is not limited to the exemplary embodiments described herein.

It is noted that the drawings are schematic, and are not illustrated based on actual scales. Relative dimensions and proportions of parts illustrated in the drawings are exaggerated or reduced in size for the purpose of clarity and convenience in the drawings, and any dimension is just illustrative but not restrictive. Further, the same reference numerals designate the same structures, elements or components illustrated in two or more drawings in order to exhibit similar characteristics.

Exemplary embodiments of the present invention illustrate ideal exemplary embodiments in more detail. As a result, various modifications of the drawings are expected. Therefore, the exemplary embodiments are not limited to specific forms in regions illustrated in the drawings, and for example, include modifications of forms by the manufacture.

Hereinafter, a free rotary fluid machine according to an exemplary embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a perspective view illustrating a rotary fluid machine according to an exemplary embodiment of the present invention, FIG. 2 is a perspective view illustrating a tip seal illustrated in FIG. 1, FIG. 3 is a perspective view illustrating a blade illustrated in FIG. 1, FIG. 4 is a view for explaining a case in which the rotary fluid machine according to the exemplary embodiment of the present invention is a turbine, FIG. 5 is a view for explaining a case in which the rotary fluid machine according to the exemplary embodiment of the present invention is a compressor, and FIG. 6 is a view for explaining a case in which the rotary fluid machine according to the exemplary embodiment of the present invention is a compander.

As illustrated in FIGS. 1 to 3, a free rotary fluid machine 100 according to an exemplary embodiment of the present invention may include: a main body 110 which is provided in a cylindrical shape and has a circular outer circumferential surface and an elliptical inner circumferential surface; a rotor 200 which is provided in the main body 110, has an approximately quadrangular cross section, and rotates about the same rotation center as the main body 110; tip seals 300 which are provided at one side of the rotor 200; auxiliary tip seals 310 each of which is formed at one end of the tip seal 300 and improves contact performance between the rotor 200 and the tip seal 300; and blades 400 which are provided between the tip seals 300 provided adjacent to each other.

Since the auxiliary tip seals 310 are formed as described above, friction between the main body 110 and the tip seals 300 is reduced, spaces formed among the main body 110, the blades 400, and the tip seals 300 are sealed, thereby preventing a leak of an introduced working fluid.

The free rotary fluid machine 100 according to the exemplary embodiment of the present invention may include the main body 110, the rotor 200, the tip seals 300, the blades 400, and the auxiliary tip seals 310.

The rotor 200, the tip seals 300, and the blades 400 may be accommodated in the main body 110. The main body 110 may be provided in a hollow cylindrical shape having a space formed therein, and the main body 110 according to the exemplary embodiment of the present invention has the outer circumferential surface which is formed in a circular shape, and the inner circumferential surface which is formed in an approximately elliptical shape different from the shape of the outer circumferential surface. However, in some instances, the outer circumferential surface of the main body, as well as the inner circumferential surface of the main body 110, may also be formed in the same elliptical shape.

The reason why the inner circumferential surface of the main body 110 is formed in an elliptical is to change volumes of operation spaces 112 for compressing or expanding a working fluid when the working fluid, which is introduced from intake ports 120 and 122 to be described below, is compressed or expanded to convert fluid energy into mechanical energy.

As described above, the main body 110 may have the intake ports through which the working fluid is introduced into the operation spaces 112, and exhaust ports through which the working fluid is discharged from the operation spaces. Specifically, at least one intake ports and at least one exhaust port may be provided in the main body 110.

As illustrated in FIG. 1, the main body 110 of the free rotary fluid machine 100 according to the exemplary embodiment of the present invention may have two intake ports 120 and 122 and two exhaust ports 130 and 132.

In this case, the intake ports 120 and 122 and the exhaust ports 130 and 132 may be provided radially based on a rotation center of the main body 110. The reason why the intake ports 120 and 122 and the exhaust ports 130 and 132 are provided radially is to improve an output of energy or pressure produced when the working fluid is introduced. In addition, in some instances, positions of the intake ports 120 and 122 and the exhaust ports 130 and 132 illustrated in FIG. 1 may vary in accordance with a rotation direction of the rotor 200 or a position or a size of the operation space 112 of the main body 110.

The rotor 200 may be provided in the main body 110 formed in an elliptical shape. The rotor 200 may be formed in a hexahedral shape having an approximately quadrangular cross section. In a case in which the rotor 200 is formed to have a quadrangular cross section, it is possible to reduce costs required to process the rotor 200. In addition, rotational force of the rotor 200 is not greatly affected even though the rotor 200 is formed to have an approximately quadrangular cross section.

The rotor 200 may have a rotating shaft 202 which is a rotation center that coincides with a center of the main body 110. Although not illustrated in the drawings, the rotating shaft 202 of the rotor 200 may be coupled to a cover (not illustrated) coupled to one side of the main body 110.

The rotor 200 is a member which is rotated in the main body 110 and on which the tip seals 300 and the blades 400, which will be described below, are mounted.

The tip seal 300 may be provided at one side of the rotor 200. Particularly, the tip seal 300 may be mounted at an edge portion of the rotor 200.

Specifically, one end portion 302 of the tip seal 300 in a longitudinal direction of the tip seal 300 may be formed in a cylindrical shape having a circular cross section, and the other end portion 304 of the tip seal 300 may be formed in a hexahedral bar shape having a quadrangular cross section. The other end portion 304 of the tip seal 300, which is formed as described above, may be coupled to a groove 204 formed at an edge portion of the rotor 200. Since the rotor 200 has a hexahedral shape having a quadrangular cross section as described above, the tip seals 300 may be provided at four edges of the quadrangular cross section of the rotor 200, one for each edge.

When the rotor 200 is rotated in the main body 110, centrifugal force is applied to the tip seal 300. When the centrifugal force is applied to the tip seal 300, the tip seal 300 is moved in the groove 204 formed at the edge of the quadrangular cross section of the rotor 200. That is, the cylindrical one end portion 302 of the tip seal 300 is moved toward an inner circumferential surface of the main body 110. When the cylindrical one end portion 302 of the tip seal 300 is moved toward the inner circumferential surface of the main body 110 by the centrifugal force as described above, one end portion 302 of the tip seal 300 may always be maintained in a state of being in contact with the inner circumferential surface of the main body 110, and as a result, it is possible to prevent the working fluid from leaking from the operation space 112.

Meanwhile, a pressing member 210 may be further provided between the rotor 200 and the tip seal 300.

The pressing member 210 may press the tip seal 300 toward the inner circumferential surface of the main body 110 when the rotor 200 is rotated, so that one end portion 302 of the tip seal 300 comes into contact with the inner circumferential surface of the main body 110. In addition, when the tip seal 300 is moved in a state of being in contact with the inner circumferential surface of the main body 110 having an elliptical shape, the tip seal 300 may elastically support the retraction of the rotor 200 toward the rotation center while moving from an inner circumferential surface of a long-radius portion of the ellipse to an inner circumferential surface of a short-radius portion of the ellipse.

The pressing member 210 according to the exemplary embodiment of the present invention may be formed in the form of a spring which has elasticity and may press the tip seal 300 against the inner circumferential surface of the main body 110, and various springs such as a coil spring, a compressive spring, and a flat spring may be applied as necessary.

However, the pressing member 210 is not always required, and the pressing member 210 may be omitted as long as the rotor 200 may be rotated in a state in which the blade 400 moves toward the inner circumferential surface of the main body 110 and thus the tip seal 300 is always maintained in a state of being in contact with the inner circumferential surface of the main body 110.

Meanwhile, the auxiliary tip seal 310 may be provided at the cylindrical one end portion 302 of the tip seal 300. The auxiliary tip seal 310 is provided to protrude from the cylindrical one end portion 302 of the tip seal 300 to the inner circumferential surface of the main body 110, thereby improving contact performance between the rotor 200 and the tip seal 300 or increasing an contact area between the rotor 200 and the tip seal 300.

Specifically, as illustrated in FIG. 2, the auxiliary tip seal 310 may include a sealing member 314, and an elastic support body 316 which pushes the sealing member 314 toward the inner circumferential surface of the main body 110 or supports the sealing member 314 when the sealing member 314 is retracted. The sealing member 314 may be drawn in (retracted into) or pulled out (drawn) from an opening 312 formed in the cylindrical one end portion 302 of the tip seal 300.

The sealing member 314 may be formed in the form of a thin plate, and the sealing member 314 according to the exemplary embodiment of the present invention may be made of a ceramic material. However, the material of the sealing member 314 may be changed as necessary as long as the material is not likely to increase friction with the inner circumferential surface of the main body 110 or damage the inner circumferential surface of the main body 110.

The elastic support body 316 may elastically support the sealing member 314.

Specifically, one end portion of the elastic support body 316 is coupled to and supports a lower end surface of the sealing member 314, and the other end portion of the elastic support body 316 may be coupled to the opening 312 of the tip seal 310. Therefore, the elastic support body 316 may enable the sealing member 314 to be drawn in (retracted into) or pulled out (drawn) from the opening 312. The elastic support body 316 according to the exemplary embodiment of the present invention may be formed in the form of a spring having elasticity, and various springs such as a flat spring and a coil spring may be applied as necessary.

Meanwhile, a width of the sealing member 314 is smaller than a width of the opening 312 considering that the inner circumferential surface of the main body 110 having an elliptical shape, such that the sealing member 314 is slightly moved in the rotation direction along a curvature of the inner circumferential surface, and as a result, a tip portion of the sealing member 314 may always be maintained in a state of being in contact with the inner circumferential surface of the main body 110.

The operation space 112 is formed by the inner circumferential surface of the main body 110, the tip seal 300, and the blade 400, and the operation space 112 is a space of which the size or the volume varies. To this end, the blade 400 may be positioned between the tip seals 300.

The blades 400 are provided between the tip seals 300 provided at the four points of the rotor 200, and both ends of the blade 400 may be supported by the tip seals 300. In this case, both ends of the blade 400 are formed in the form of a curved surface so that the blade 400 are in surface-to-surface contact with the cylindrical one end portion 302 of the tip seal 300, and as a result, it is possible to stably maintain surface-to-surface contact or coupling between the tip seals 300 and the blade 400.

As illustrated in FIG. 3, the blade 400 may be formed in a shape having an inverted trapezoidal cross section. One end surface 402 and the other end surface 404 of the blade 400 in a thickness direction of the blade 400, that is, an upper surface and a lower surface of the blade 400 are different in length from each other.

A length of one end surface 402 of the blade 400 according to the exemplary embodiment of the present invention may be longer than a length of the other end surface 404.

The reason is that tip seal contact portions 403 between one end surface 402 and the other end surface 404 in the thickness direction of the blade 400 need to be formed in the form of a curved surface because both ends of the blade 400 are fitted between the two neighboring tip seals 300 while being in surface-to-surface contact with the cylindrical one end portion 302 of the tip seal 300, and in this case, a curvature of the curved surface of the tip seal contact portion 403, which connects one end surface 402 and the other end surface 404, may be equal to a curvature of the cylindrical one end portion 302 of the tip seal 300.

In addition, a portion where the tip seal contact portion 403 meets one end surface 402 of the blade 400 is positioned at an upper end portion of the cylindrical one end portion 302 of the tip seal 300, and this portion may be formed to be rounded, that is, formed to have a predetermined radius of curvature instead of being formed to be angled.

Therefore, it is possible to prevent the blade 400 or the tip seal 300 from being damaged as the blade 400 is stuck into the cylindrical one end portion 302 of the tip seal 300 or causes friction due to the portion where the tip seal contact portion 403 meets one end surface 402 of the blade 400 when the tip seal contact portion 403 of the blade 400 is rotated in the inner circumferential surface of the main body 110.

Specifically, in a case in which the portion where the one end surface 402 of the blade 400 meets the tip seal contact portion 403 is formed to be exactly matched with the cylindrical one end portion 302 of the tip seal 300, the blade 400 may be more stably supported by the tip seal 300.

Meanwhile, both ends of the blade 400 in the longitudinal direction of the blade 400, that is, the tip seal contact portions 403 may be formed, if possible, to have a large contact area with the cylindrical one end portion 302 of the tip seal 300 or have a long length. Referring to FIG. 1, it can be seen that the tip seal contact portion 403 is in contact with the tip seal 300 from a point at which the cylindrical one end portion 302 of the tip seal 300 meets the other end portion 304 of the tip seal 300.

That is, according to the blade 400 of the free rotary fluid machine 100 according to the exemplary embodiment of the present invention, to increase a contact area in which the tip seal contact portion 403 and the tip seal 300 are in direct contact with each other, one end surface 402 and the other end surface 404 of the blade 400 are formed in the form of a curved surface, and centers of radii of curvature of one end surface 402 and the other end surface 404 of the blade 400 are positioned at the same side based on the blade 400. With the aforementioned configuration, when the blade 400 is moved toward the inner circumferential surface of the main body 110 as the rotor 200 is rotated at a high speed, the tip seals 300, which are in contact with and support both ends of the blade 400 while maintaining the surface-to-surface contact state between the blade 400 and the tip seals 300, are also moved toward the inner circumferential surface of the main body 110, such that the tip seals 300 may be in close contact with the inner circumferential surface of the main body 110, and as a result, it is possible to prevent a leak caused by destruction of the surface-to-surface contact state between the tip seals 300 and both ends of the blade 400, and thus to prevent the situation in which the blade 400 cannot be rotated.

An operation of the free rotary fluid machine 100 according to the exemplary embodiment of the present invention, which has the aforementioned structures, will be described with reference to FIGS. 4 to 6.

Here, the free rotary fluid machine 100 according to the exemplary embodiment of the present invention may be applied as various forms such as a turbine, a compressor, a pump, an engine, and a compander (a combination of a compressor and an expander).

Assuming that the rotor 200 of the free rotary fluid machine 100 according to the present invention is rotated counterclockwise as illustrated in FIGS. 4 to 6, reference numerals 120 and 122 indicate the intake ports, and reference numerals 130 and 132 indicate the exhaust ports.

In this case, as illustrated in FIG. 4, if the free rotary fluid machine 100 according to the exemplary embodiment of the present invention is a turbine, the intake ports 120 and 122 may be formed at positions at which the tip seal 300 and the auxiliary tip seal 310 are in close contact with the inner circumferential surface of the main body 110, and the exhaust ports 130 and 132 may be formed at positions at which the operation space 112 formed between the inner circumferential surface of the main body 110 and the rotor 200 has a largest volume.

As the free rotary fluid machine 100 operates as a turbine in accordance with the positions of the intake ports 120 and 122 and the exhaust ports 130 and 132, a working fluid such as steam, air, and gas may be introduced through the intake ports 120 and 122. Then, the introduced working fluid rotates the rotor 200 while pushing the tip seal 300 and the blade 400, the working fluid is expanded in a large space so as to expand a volume of the operation space 12, and then the working fluid may be discharged through the exhaust ports 130 and 132.

Meanwhile, as illustrated in FIG. 5, if the free rotary fluid machine 100 according to the exemplary embodiment of the present invention is a compressor, the intake ports 120 and 122 through which a working fluid is introduced may be formed at positions at which the operation space 112 formed between the inner circumferential surface of the main body 110 and the rotor 200 has a largest volume, and the exhaust ports 130 and 132 through which the working fluid is discharged may be formed at positions adjacent to positions at which the tip seal 300 and the auxiliary tip seal 310 are in contact with the inner circumferential surface of the main body 110.

As the free rotary fluid 110 operates as a compressor in accordance with the positions of the intake ports 120 and 122 and the exhaust ports 130 and 132, the operation space 112 formed between the main body 110 and the rotor is filled with the working fluid, and the working fluid is compressed when the rotor 200 is rotated and thus a volume of the operation space 112 formed between the main body 11 and the rotor 200 is decreased. The compressed working fluid may be discharged through the exhaust ports 130 and 132.

That is, in a case in which the free rotary fluid machine 100 is a compressor, the positions of the intake ports 120 and 122 and the exhaust ports 130 and 132 may be different from the positions of the intake ports and the exhaust ports in a case in which the free rotary fluid machine 100 is a turbine.

As illustrated in FIG. 6, the free rotary fluid machine 100 according to the exemplary embodiment of the present invention may operate as a compander. Here, the compander refers to a single free rotary fluid machine 100 that performs operations of a compressor and an expander.

In a case in which the free rotary fluid machine 100 is a compander, the intake ports 120 and 122 may be formed at a position at which the tip seal 300 and the auxiliary tip seal 310 are in close contact with the inner circumferential surface of the main body 110 and at a position at which the operation space 112 formed between the inner circumferential surface of the main body 110 and the rotor 200 has a largest volume, respectively, and the exhaust ports 130 and 132, through which the working fluid is discharged, may be formed at a position at which the operation space 112 formed between the inner circumferential surface of the main body 110 and the rotor 200 has a largest volume and at a position adjacent to a position at which the tip seal 300 and the auxiliary tip seal 310 are in contact with the inner circumferential surface of the main body 110.

As the free rotary fluid machine 100 operates as a compander in accordance with the positions of the intake ports 120 and 122 and the exhaust ports 130 and 132, the operation space 112 formed between the main body 110 and the rotor 200 is filled with the working fluid introduced through the intake port 120, and the working fluid may be compressed when the rotor 200 is rotated and thus a volume of the operation space 112 formed between the main body 110 and the rotor 200 is decreased. The compressed working fluid is discharged through the exhaust port 132. In addition, the working fluid introduced through the intake port 122 rotates the rotor 200 while pushing the tip seal 300 and the blade 400, the working fluid is expanded in a large space so as to expand a volume of the operation space 112, and then the working fluid may be discharged through the exhaust port 130.

Here, frictional force, which may occur between the main body 110 and the rotor 200, is reduced by the tip seal 300 and the auxiliary tip seal 310 formed in the tip seal 300, and as a result, it is possible to increase rotational force of the rotor 200 and improve sealing performance between the inner circumferential surface of the main body 110 and the tip seal 300 or the auxiliary tip seal 310.

As described above, according to the free rotary fluid machine 100 according to the present invention, the auxiliary tip seal 310 is formed to protrude from the tip seal 300, such that contact performance or sealing performance between the inner circumferential surface of the main body 110 and the tip seal 300 is improved when the rotor 200 is rotated, and as a result, it is possible to seal the operation space 112 formed among the inner circumferential surface of the main body 110, the rotor 200, and the tip seal 300.

In addition, according to the exemplary embodiments of the present invention, the operation space 112 formed among the inner circumferential surface of the main body 110, the rotor 200, and the tip seal 300 is sealed by the auxiliary tip seal 310, and as a result, it is possible to reduce friction between the tip seal 300 and the main body 110 and to prevent a leak of the introduced working fluid.

In addition, according to the exemplary embodiments of the present invention, since the auxiliary tip seal 310 is drawn in (retracted into) and pulled out (drawn) from the tip seal 300, the tip seals 300 may be moved in a state in which both ends of the blade 400, which are supported between the tip seals 300 provided adjacent to each other, that is, the tip seal contact portions 403 are maintained in a state of being in surface-to-surface contact with the tip seals 300.

In addition, according to the exemplary embodiments of the present invention, the pressing member 210 is provided between the tip seal 300 and the rotor 200, and as a result, it is possible to maintain a state in which the tip seal 300 is pressed against the inner circumferential surface of the main body 110, and it is possible to elastically support the tip seal 300 when the tip seal 300 is retracted toward the rotating shaft 202 of the rotor 200.

While the exemplary embodiments of the present invention have been described with reference to the accompanying drawings, those skilled in the art will understand that the present invention may be implemented in any other specific form without changing the technical spirit or an essential feature thereof.

Accordingly, it should be understood that the aforementioned exemplary embodiments are described for illustration in all aspects and are not limited, and the scope of the present invention shall be represented by the claims to be described below, and it should be construed that all of the changes or modified forms induced from the meaning and the scope of the claims, and an equivalent concept thereto are included in the scope of the present invention.

INDUSTRIAL APPLICABILITY

The present invention may be applied to a fluid machine, a free rotary fluid machine, and the like. 

1. A free rotary fluid machine comprising: a main body which is provided in a hollow cylindrical shape, and has an elliptical inner circumferential surface; a rotor which is provided in the main body, and rotates about the same rotation center as the main body; tip seals which are provided at one side of the rotor so as to be in contact with the inner circumferential surface of the main body; and blades which are provided between the tip seals provided adjacent to each other, and supported by the tip seals, wherein the blade has one end surface that faces the inner circumferential surface of the main body, and the other end surface that is opposite to one end surface, and centers of radii of curvature of one end surface and the other end surface are positioned at the same side.
 2. The free rotary fluid machine of claim 1, wherein the blade has tip seal contact portions that connect one end surface and the other end surface, and the tip seal contact portion is formed to have the same curved surface as the tip seal.
 3. The free rotary fluid machine of claim 2, wherein one end portion of the tip seal in a longitudinal direction of the tip seal is formed in a cylindrical shape having a circular cross section and is in contact with the inner circumferential surface of the main body, the other end portion of the tip seal is formed in a hexahedral bar shape having a quadrangular cross section, and the tip seal contact portion is in surface-to-surface contact with one end portion from a point at which one end portion meets the other end portion.
 4. The free rotary fluid machine of claim 3, wherein a portion where the tip seal contact portion meets one end portion is formed to have a curved surface.
 5. The free rotary fluid machine of claim 3, wherein an auxiliary tip seal, which is formed to protrude toward the inner circumferential surface of the main body, is provided at one end portion of the tip seal, and the auxiliary tip seal is rotated by the rotor while maintaining a surface-to-surface contact state with the inner circumferential surface of the main body.
 6. The free rotary fluid machine of claim 5, wherein the auxiliary tip seal includes: a sealing member which is drawn in or pulled out from the tip seal; and an elastic support body which supports the sealing member and enables the sealing member to be drawn in or pulled out from the tip seal.
 7. The free rotary fluid machine of claim 6, wherein the sealing member is made of a ceramic material.
 8. The free rotary fluid machine of claim 1, further comprising: a pressing member which is provided between the tip seal and the rotor and elastically presses the tip seal.
 9. The free rotary fluid machine of claim 6, wherein a width of the sealing member is smaller than a width of an opening which is formed at one end portion of the tip seal such that the sealing member is inserted into the opening.
 10. The free rotary fluid machine of claim 1, wherein at least one intake port and at least one exhaust port are provided in the main body, and the intake port and the exhaust port are provided radially based on the rotation center of the main body. 